In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated the...In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated their abilities in retrieving terrestrial water storage(TWS)changes over the Amazon River Basin(ARB)from January 2003 to February 2013.The performance of the weekly GPD-SH and GPDmascon solutions was evaluated by comparing them with the weekly GFZ-SH solutions,Global Land Data Assimilation Systems(GLDAS)-NOAH hydrological model outputs,and monthly GFZ-SH,GPD-SH,and CSRmascon solutions in the spatio-temporal and spectral domains.The results demonstrate that the weekly GPD-SH and GPD-mascon present good consistency with the weekly GFZ-SH solutions and GLDAS-NOAH estimates in the spatio-temporal domains,but GPD-mascon presents stronger signal amplitudes and more spatial details.The comparison of the monthly average of weekly estimates and monthly solutions demonstrates that the weekly GPD-mascon and GFZ-SH with DDK1 filtering are close to the monthly CSRmascon and GFZ-SH solutions,respectively.However,the signal amplitudes of TWS changes from GPD-SH and GFZ-SH with 650 km Gaussian filtering are smaller than the monthly solutions,and the corresponding Root Mean Square Errors between the TWS change time series from the monthly average of weekly solutions and monthly estimates are 18.12 mm(GPD-mascon),18.81 mm(GFZ-SH-DDK1),24.93 mm(GPDSH-G650km),and 33.07 mm(GFZ-SH-G650km),respectively.Additionally,the TWS change time series derived from weekly solutions present more high-frequency time-varying information than monthly solutions.Furthermore,the 300 km Gaussian filtering can improve the signal amplitudes of TWS changes from the weekly GPD-SH solutions more than those with 650 km Gaussian filtering,but the corresponding noise level is higher.The weekly GPD-SH and GPD-mascon solutions can extend the application scopes of GRACE and provide good complements to the current GRACE monthly solutions.展开更多
We explore the impacts of economic and financial dislocations caused by COVID-19 pandemic shocks on food sales in the United States from January 2020 to January 2021.We use the US weekly economic index(WEI)to measure ...We explore the impacts of economic and financial dislocations caused by COVID-19 pandemic shocks on food sales in the United States from January 2020 to January 2021.We use the US weekly economic index(WEI)to measure economic dislocations and the Chicago Board Options Exchange volatility index(VIX)to capture the broader stock market dislocations.We validate the NARDL model by testing a battery of models using the autoregressive distributed lags(ARDL)methodology(ARDL,NARDL,and QARDL specifications).Our study postulates that an increase in WEI has a significant negative long-term effect on food sales,whereas a decrease in WEI has no statistically significant(long-run)effect.Thus,policy responses that ignore asymmetric effects and hidden cointegration may fail to promote food security during pandemics.展开更多
In the international communist movement in the 19th century,the national uprising in Europe and the workers’movement were intertwined,forming a complex historical background.The Polish National Uprising in 1863 becam...In the international communist movement in the 19th century,the national uprising in Europe and the workers’movement were intertwined,forming a complex historical background.The Polish National Uprising in 1863 became a historical opportunity for the establishment of the First International.Although the unity of the British workers and the French workers was the realistic basis of the First International,the French workers showed a vague attitude different from the British workers on the Polish issue.In the first Congress of the First International,the French workers who almost are Proudhonists rejected the issue of supporting the Polish nation against the Tsar Russian oppression.Pierre-Joseph Proudhon did not link the Polish issue with the workers’movement,while he insisted that social and economic issues should not be confused with political reconstruction,and artificially separated national revival from workers’liberation.In order to promote and assist the establishment of the First International,Marx made certain consideration and concessions on national issues in the formulation of its declaration and constitution.Then Engels,commissioned by Marx,made some specific interpretations that they based on the difference between nation and nationality,and adhere it to the international national principle,both clearly shows the Marxism view of nation state,reveals the risk if international communist movement limited to the principle of nationalities,and also further reveals the importance to combine two great cause,national revival and workers liberation.展开更多
This paper explores the pathways through which artificial intelligence(AI)enhances new quality productivity in new liberal arts education.By analyzing the role of AI in personalized learning,interdisciplinary integrat...This paper explores the pathways through which artificial intelligence(AI)enhances new quality productivity in new liberal arts education.By analyzing the role of AI in personalized learning,interdisciplinary integration,and the application of virtual reality/augmented reality technologies,it reveals how AI technology promotes the development of students’innovative capabilities and productivity in the context of new liberal arts education.The study shows that AI is not only a technical tool but also a driving force for transforming educational models and fostering knowledge innovation.Further exploration of the deep integration of AI and new liberal arts education is necessary to promote comprehensive social progress.展开更多
English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of c...English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of college English teaching,and online teaching has not been widely used.Under the background of new liberal arts,the teaching tasks and objectives of college English have changed,and it is imperative to carry out online-offline hybrid teaching mode.This paper analyzes the feasibility of the online-offline hybrid teaching mode of college English,summarizes its problems,and explores its implementation strategies in the context of the new liberal arts,to provide references for teachers.展开更多
Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differen...Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differences.These differences,compounded by the demands of the new liberal arts reform,place significant challenges and pressure on elective course instructors.To meet these demands,elective course teachers should enhance their teaching methods and explore new instructional models.The International Trade in Services course,for instance,has implemented six areas of curriculum reform,enriching the practice of elective course improvement.展开更多
The concept of New Liberal Arts,a multidisciplinary combined integrator with Chinese values at its core,has brought new challenges to the teaching methods and professional development of higher-level English teachers....The concept of New Liberal Arts,a multidisciplinary combined integrator with Chinese values at its core,has brought new challenges to the teaching methods and professional development of higher-level English teachers.Based on the evolving professional development process of higher vocational English teachers in the context of the New Liberal Arts,this article analyzes how English teachers can integrate multidisciplinary knowledge and adopt advanced educational technology in the teaching process.On this basis,it discusses the role of teachers’professional development in enhancing students’learning ability,such as through deepening disciplinary understanding,adopting innovative teaching strategies,and implementing personalized teaching.At the end of the article,based on a variety of pedagogical theories,we put forward suggestions,including continuous professional training,interdisciplinary cooperation,and the application of innovative teaching techniques,which are mainly aimed at helping higher vocational English teachers get rid of the dilemma of the new situation,adapt to the needs of the new liberal arts education as soon as possible,and then effectively improve students’abilities.展开更多
This paper reviews the origin and history of sexism in English language and the cause of it,and analysizes the history and development of Women's Liberation and the effects of Women's Liberation movement in En...This paper reviews the origin and history of sexism in English language and the cause of it,and analysizes the history and development of Women's Liberation and the effects of Women's Liberation movement in English language.展开更多
The associated minerals make coal middlings possess a relatively high ash content.Subsequent liberation through size reduction can cause recovery increase.However,effect of comminution facilities on mineral liberation...The associated minerals make coal middlings possess a relatively high ash content.Subsequent liberation through size reduction can cause recovery increase.However,effect of comminution facilities on mineral liberation of middlings was ignored.This paper studied the liberation characteristics of middlings crushed with different kinds of fragmentation forces.Middlings of 3 mm+0.5 mm sampled from a dense medium cyclone were comminuted by a jaw crusher and a ball mill to 0.5 mm with similar size distribution respectively.The generating mechanism of fnes was also analyzed.Full densimetric analyses indicate that mineral liberation of the product crushed by the jaw crusher is better than that by the ball mill at each fraction.For sizes of 0.125 mm+0.074 mm and 0.074 mm,yields of the product with ash content 11%comminuted by jaw crusher are nearly 20%higher than that by the ball mill.Sectional micrographs observed by the scanning electron microscopy(SEM)also show the same law for these two fractions and some intergrowth particles still exist in the fraction of 0.5 mm+0.25 mm.展开更多
This study involved the investigation of the effects of the continuous cooling process conditions on the crystallization and liberation characteristics of anosovite in Ti-bearing titanomagnetite smelting slag. The sam...This study involved the investigation of the effects of the continuous cooling process conditions on the crystallization and liberation characteristics of anosovite in Ti-bearing titanomagnetite smelting slag. The samples were heated until melting and then the temperature was held at 1650℃ for nearly 0.5 h;subsequently, the samples were cooled at different cooling rates to different temperatures and water-quenched after being held for different times at these temperatures. Last, the obtained crystallized samples were used to analyze the crystallization and liberation characteristics. It was found that, during the continuous cooling process, anosovite particles were found to initially precipitate in the slag at a relatively high crystallization temperature, showing the characteristics of euhedral crystal. The precipitation and growth of anosovite grain is strong and the morphology of anosovite was basically not affected by the continuous cooling conditions. From the morphology perspective, the formed anosovite is an excellent Ti-rich phase to be selective separated. The formation of spinel and diopside is negative for the liberation and selective separation of the anosovite phase. The crystallization diagrams of TiO2-MgO-CaO-SiO2-Al2O3-FeO slag undergoing different continuous cooling processes were constructed to help to determine the optimal continuous cooling–quenching condition for selective separation of anosovite. Moreover, the addition of B2O3 can enlarge the range of the optimal continuous cooling–quenching conditions for selective separation of anosovite.展开更多
In this study,we administered a modified schedule of weekly intravenous Bortezomib at 1.6 mg/m 2 with dexamethasone(BD) and compared it to the standard 1.3 mg/m 2 twice-weekly BD regimen in Chinese patients with newly...In this study,we administered a modified schedule of weekly intravenous Bortezomib at 1.6 mg/m 2 with dexamethasone(BD) and compared it to the standard 1.3 mg/m 2 twice-weekly BD regimen in Chinese patients with newly diagnosed multiple myeloma(MM).We assessed the difference in efficacy,safety profile and survival between the once-weekly and twice-weekly cohorts(13 vs.24 patients).The over response rate was similar with both arms of the study,being 77% in the once-weekly schedule and 74.9% in the twice-weekly schedule(P=0.690).The median overall survival was not reached in either schedule.Also,the median progression-free survival and duration of response of the once-weekly schedule did not significantly differ from those of the twice-weekly schedule(8 months vs.10 months,P=0.545 and 6 months vs.7 months,P=0.467 respectively).Peripheral sensory neuropathy and grade 3/4 hematologic toxic effects were more frequently reported in the twice-weekly schedule than the once-weekly schedule,but there was no statistically significant difference.This preliminary experience in Chinese patients with newly diagnosed MM indicated that once-weekly infusion of Bortezomib plus dexamethasone may improve safety without affecting outcome.展开更多
The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mos...The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mostly of quartz, topaz and zinnwaldite (Li-rich mica) were exposed to further comminution by cone crusher and high voltage pulse power fragmentation. Product properties were analyzed by using a Mineral Liberation Analyser (MLA) and the obtained mineralogical and mineral processing relevant parameters were carefully evaluated with special focus on the characteristics of zinnwaldite. The results illustrate that both samples contain a significant quantity of very fine particles that are products of comminution. The modal mineralogy in the different sieve fractions is characterized by the accumulation of minerals of low hardness in the finest fraction and the enrichment of topaz, having a high hardness, in the somewhat larger fractions. Based on the results of mineral association data for zinnwaldite, a displacement of the muscovite-quartz ratio, in comparison to the results of modal mineralogy, was observed by indicating good quartz-zinnwaldite boundary breakage and weak muscovite-zinnwaldite breakage. Liberation as well as mineral grade recovery curves indicate that fraction 1000 to +500 μm is most suitable for beneficiation. The results of this study demonstrate that SEM-based image analysis, such as MLA, can effectively be used to investigate and evaluate phyllosilicate minerals in a fast and precise way. It is shown that the results of MLA investigations, such as modal mineralogy, are in good agreement with other analytical methods such as quantitative X-ray powder diffraction.展开更多
As ore grades constantly decline,more copper tailings,which still contain a considerable amount of unrecovered copper,are expected to be produced as a byproduct of froth flotation.This research reveals the occurrence ...As ore grades constantly decline,more copper tailings,which still contain a considerable amount of unrecovered copper,are expected to be produced as a byproduct of froth flotation.This research reveals the occurrence mechanism of copper minerals in typical copper sulfide tailings using quantitative mineral liberation analysis(MLA)integrated with scanning electron microscopy–energy dispersive spectroscopy(SEM–EDS).A comprehensive mineralogical characterization was carried out,and the results showed that almost all copper minerals were highly disseminated within coarse gangue particles,except for 9.2wt%chalcopyrite that occurred in the 160–180μm size fraction.The predominant copper-bearing mineral was chalcopyrite,which was closely intergrown with orthoclase and muscovite rather than quartz.The flotation tailings sample still contained 3.28wt%liberated chalcopyrite and 3.13wt%liberated bornite because of their extremely fine granularity.The SEM–EDS analysis further demonstrated that copper minerals mainly occurred as fine dispersed and fully enclosed structures in gangue minerals.The information obtained from this research could offer useful references for recovering residual copper from flotation tailings.展开更多
The removal of iron from an Indian diaspore sample was studied using magnetic separation and leaching techniques aided by an in-depth mineralogical characterization study involving quantitative mineralogical evaluatio...The removal of iron from an Indian diaspore sample was studied using magnetic separation and leaching techniques aided by an in-depth mineralogical characterization study involving quantitative mineralogical evaluation by scanning electron microscope(QEMSCAN), electron probe micro-analyzer(EPMA) and X-ray diffraction(XRD). The characterization studies indicate that extremely fine-sized hematite grains are associated with several other mineral phases in a complex manner with around 60% of the hematite not liberated even below the size of 38 μm limiting the scope of physical separation processes to remove the iron. Wet high intensity magnetic separation(WHIMS) studies reveal that only 49% of iron can be removed. Further, leaching studies using oxalic acid suggest that around 76% of the iron can be removed under conditions such as a solid to liquid ratio of 0.05:1, a temperature of 90 ℃ a time period of 120 min and an acid concentration of 1 mol/L. The dissolution of iron in oxalic acid is found to be controlled by chemical reaction and the activation energy is calculated as 35.15 k J/mol.展开更多
The influence of microwave treatment on the liberation of iron ore from the high phosphorus oolitic iron ore from Aswan region, Egypt was studied. The effect of microwave power, exposure time and grain size on the lib...The influence of microwave treatment on the liberation of iron ore from the high phosphorus oolitic iron ore from Aswan region, Egypt was studied. The effect of microwave power, exposure time and grain size on the liberation of iron ore was investigated. The microfractures and cracks of the samples were characterized before and after microwave treatments. The heating rate of high phosphorus oolitic iron ore was studied. Crystallinity of hematite was characterized before and after microwave pretreatment. The results indicated that intergranular fractures formed between the gangues (fluorapatite and chamosite) and hematite after microwave treatment, leading to improved liberation of iron ore and a significant reduction in comminution energy. Percentages of fraction ≤ -0.125 mm increased from 46.6% to 59.76% with increased exposure time from 0 to 60 seconds. The heating rate of iron ore showed that microwave treatment was less efficient at smaller particle sizes for a fixed applied power density. Crystallinity of hematite increased with the microwave exposure time.展开更多
AIM:To investigate variations in the incidence of peptic ulcers(PUs) in Taiwan by day of the week within age subgroups.METHODS:Ambulatory care data were retrieved from the Longitudinal Health Insurance Database 2000.T...AIM:To investigate variations in the incidence of peptic ulcers(PUs) in Taiwan by day of the week within age subgroups.METHODS:Ambulatory care data were retrieved from the Longitudinal Health Insurance Database 2000.There were 7204 subjects≥18 years-old with an emergency room admission claim for the treatment of PUs,resulting in a total of 9234 emergency room visits for PUs between 2009 and 2011.Data was divided into the seven days of the week and an additional variable for holidays.One-way analysis of variance was used to examine associations among the daily mean number of PU emergency room admissions and holidays/weekends/weekdays.RESULTS:One-way analysis of variance showed that there was a significant difference in emergency room admissions for PUs by the day of the week(P<0.001),with admission more likely to occur on Sundays or holidays than weekdays within the total and working populations.The weekday patterns of admission were similar for the patients aged 18-64 years and≥65years of age.Holidays,followed by Sundays,had higher PU admissions than the mean daily PU emergency room admissions.Furthermore,inclusion of only those treated for PUs with hemorrhage or perforation,Sundays and holidays had higher mean emergency room admissions than other days.Inclusion of patients who diagnosed with Helicobacter pylori infection,only holidays had higher mean emergency room admissions than other days.Inclusion of patients who had been prescribed non-steroidal anti-inflammatory drugs(NSAIDs)for over30 d,Sundays and holidays had higher mean PU ER admissions than other non-holiday weekdays.CONCLUSION:There is a higher incidence of emergency room admission for PUs on weekends than on weekdays for the total and working populations.展开更多
基金funded by the National Natural Science Foundation of China(Nos.41974015,42374002)the Project Supported by the Special Fund of Hubei Luojia Laboratory(No.220100004)。
文摘In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated their abilities in retrieving terrestrial water storage(TWS)changes over the Amazon River Basin(ARB)from January 2003 to February 2013.The performance of the weekly GPD-SH and GPDmascon solutions was evaluated by comparing them with the weekly GFZ-SH solutions,Global Land Data Assimilation Systems(GLDAS)-NOAH hydrological model outputs,and monthly GFZ-SH,GPD-SH,and CSRmascon solutions in the spatio-temporal and spectral domains.The results demonstrate that the weekly GPD-SH and GPD-mascon present good consistency with the weekly GFZ-SH solutions and GLDAS-NOAH estimates in the spatio-temporal domains,but GPD-mascon presents stronger signal amplitudes and more spatial details.The comparison of the monthly average of weekly estimates and monthly solutions demonstrates that the weekly GPD-mascon and GFZ-SH with DDK1 filtering are close to the monthly CSRmascon and GFZ-SH solutions,respectively.However,the signal amplitudes of TWS changes from GPD-SH and GFZ-SH with 650 km Gaussian filtering are smaller than the monthly solutions,and the corresponding Root Mean Square Errors between the TWS change time series from the monthly average of weekly solutions and monthly estimates are 18.12 mm(GPD-mascon),18.81 mm(GFZ-SH-DDK1),24.93 mm(GPDSH-G650km),and 33.07 mm(GFZ-SH-G650km),respectively.Additionally,the TWS change time series derived from weekly solutions present more high-frequency time-varying information than monthly solutions.Furthermore,the 300 km Gaussian filtering can improve the signal amplitudes of TWS changes from the weekly GPD-SH solutions more than those with 650 km Gaussian filtering,but the corresponding noise level is higher.The weekly GPD-SH and GPD-mascon solutions can extend the application scopes of GRACE and provide good complements to the current GRACE monthly solutions.
基金financial interest(such as honorariaeducational grants+2 种基金participation in speakers’bureausmembership,employment,consultancies,stock ownership,or other equity interestand expert testimony or patent-licensing arrangements),or nonfinancial interest(such as personal or professional relationships,affiliations,knowledge or beliefs)in the subject matter or materials discussed in this manuscript.
文摘We explore the impacts of economic and financial dislocations caused by COVID-19 pandemic shocks on food sales in the United States from January 2020 to January 2021.We use the US weekly economic index(WEI)to measure economic dislocations and the Chicago Board Options Exchange volatility index(VIX)to capture the broader stock market dislocations.We validate the NARDL model by testing a battery of models using the autoregressive distributed lags(ARDL)methodology(ARDL,NARDL,and QARDL specifications).Our study postulates that an increase in WEI has a significant negative long-term effect on food sales,whereas a decrease in WEI has no statistically significant(long-run)effect.Thus,policy responses that ignore asymmetric effects and hidden cointegration may fail to promote food security during pandemics.
文摘In the international communist movement in the 19th century,the national uprising in Europe and the workers’movement were intertwined,forming a complex historical background.The Polish National Uprising in 1863 became a historical opportunity for the establishment of the First International.Although the unity of the British workers and the French workers was the realistic basis of the First International,the French workers showed a vague attitude different from the British workers on the Polish issue.In the first Congress of the First International,the French workers who almost are Proudhonists rejected the issue of supporting the Polish nation against the Tsar Russian oppression.Pierre-Joseph Proudhon did not link the Polish issue with the workers’movement,while he insisted that social and economic issues should not be confused with political reconstruction,and artificially separated national revival from workers’liberation.In order to promote and assist the establishment of the First International,Marx made certain consideration and concessions on national issues in the formulation of its declaration and constitution.Then Engels,commissioned by Marx,made some specific interpretations that they based on the difference between nation and nationality,and adhere it to the international national principle,both clearly shows the Marxism view of nation state,reveals the risk if international communist movement limited to the principle of nationalities,and also further reveals the importance to combine two great cause,national revival and workers liberation.
基金Guangdong Association for Non-Government Education,2024 Private University Research Project(GMG2024019)Guangzhou College of Commerce,2024 Higher Education Teaching Reform Project(2024JXGG49)China Association of Higher Education,2023 Higher Education Scientific Research Planning Project(23SZH0416)。
文摘This paper explores the pathways through which artificial intelligence(AI)enhances new quality productivity in new liberal arts education.By analyzing the role of AI in personalized learning,interdisciplinary integration,and the application of virtual reality/augmented reality technologies,it reveals how AI technology promotes the development of students’innovative capabilities and productivity in the context of new liberal arts education.The study shows that AI is not only a technical tool but also a driving force for transforming educational models and fostering knowledge innovation.Further exploration of the deep integration of AI and new liberal arts education is necessary to promote comprehensive social progress.
基金Research and Practice of College English Writing Mixed Teaching Model Under the Guidance of OBE Concept of Education Reform Project of Guangdong Technology College(Project number:JXGG2024089)。
文摘English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of college English teaching,and online teaching has not been widely used.Under the background of new liberal arts,the teaching tasks and objectives of college English have changed,and it is imperative to carry out online-offline hybrid teaching mode.This paper analyzes the feasibility of the online-offline hybrid teaching mode of college English,summarizes its problems,and explores its implementation strategies in the context of the new liberal arts,to provide references for teachers.
文摘Variations in the allocation of university resources,teachers’course selection preferences and teaching commitment levels,as well as students’course preferences and assessment requirements,create subjective differences.These differences,compounded by the demands of the new liberal arts reform,place significant challenges and pressure on elective course instructors.To meet these demands,elective course teachers should enhance their teaching methods and explore new instructional models.The International Trade in Services course,for instance,has implemented six areas of curriculum reform,enriching the practice of elective course improvement.
文摘The concept of New Liberal Arts,a multidisciplinary combined integrator with Chinese values at its core,has brought new challenges to the teaching methods and professional development of higher-level English teachers.Based on the evolving professional development process of higher vocational English teachers in the context of the New Liberal Arts,this article analyzes how English teachers can integrate multidisciplinary knowledge and adopt advanced educational technology in the teaching process.On this basis,it discusses the role of teachers’professional development in enhancing students’learning ability,such as through deepening disciplinary understanding,adopting innovative teaching strategies,and implementing personalized teaching.At the end of the article,based on a variety of pedagogical theories,we put forward suggestions,including continuous professional training,interdisciplinary cooperation,and the application of innovative teaching techniques,which are mainly aimed at helping higher vocational English teachers get rid of the dilemma of the new situation,adapt to the needs of the new liberal arts education as soon as possible,and then effectively improve students’abilities.
文摘This paper reviews the origin and history of sexism in English language and the cause of it,and analysizes the history and development of Women's Liberation and the effects of Women's Liberation movement in English language.
基金supported financially by the National Natural Science Foundation of China(No.5107415651274196 and51221462)the Natural Youth Science Foundation of China(No.51104160)
文摘The associated minerals make coal middlings possess a relatively high ash content.Subsequent liberation through size reduction can cause recovery increase.However,effect of comminution facilities on mineral liberation of middlings was ignored.This paper studied the liberation characteristics of middlings crushed with different kinds of fragmentation forces.Middlings of 3 mm+0.5 mm sampled from a dense medium cyclone were comminuted by a jaw crusher and a ball mill to 0.5 mm with similar size distribution respectively.The generating mechanism of fnes was also analyzed.Full densimetric analyses indicate that mineral liberation of the product crushed by the jaw crusher is better than that by the ball mill at each fraction.For sizes of 0.125 mm+0.074 mm and 0.074 mm,yields of the product with ash content 11%comminuted by jaw crusher are nearly 20%higher than that by the ball mill.Sectional micrographs observed by the scanning electron microscopy(SEM)also show the same law for these two fractions and some intergrowth particles still exist in the fraction of 0.5 mm+0.25 mm.
基金financially supported by the National Natural Science Foundation of China (Nos. 51404226 and 21736010)
文摘This study involved the investigation of the effects of the continuous cooling process conditions on the crystallization and liberation characteristics of anosovite in Ti-bearing titanomagnetite smelting slag. The samples were heated until melting and then the temperature was held at 1650℃ for nearly 0.5 h;subsequently, the samples were cooled at different cooling rates to different temperatures and water-quenched after being held for different times at these temperatures. Last, the obtained crystallized samples were used to analyze the crystallization and liberation characteristics. It was found that, during the continuous cooling process, anosovite particles were found to initially precipitate in the slag at a relatively high crystallization temperature, showing the characteristics of euhedral crystal. The precipitation and growth of anosovite grain is strong and the morphology of anosovite was basically not affected by the continuous cooling conditions. From the morphology perspective, the formed anosovite is an excellent Ti-rich phase to be selective separated. The formation of spinel and diopside is negative for the liberation and selective separation of the anosovite phase. The crystallization diagrams of TiO2-MgO-CaO-SiO2-Al2O3-FeO slag undergoing different continuous cooling processes were constructed to help to determine the optimal continuous cooling–quenching condition for selective separation of anosovite. Moreover, the addition of B2O3 can enlarge the range of the optimal continuous cooling–quenching conditions for selective separation of anosovite.
文摘In this study,we administered a modified schedule of weekly intravenous Bortezomib at 1.6 mg/m 2 with dexamethasone(BD) and compared it to the standard 1.3 mg/m 2 twice-weekly BD regimen in Chinese patients with newly diagnosed multiple myeloma(MM).We assessed the difference in efficacy,safety profile and survival between the once-weekly and twice-weekly cohorts(13 vs.24 patients).The over response rate was similar with both arms of the study,being 77% in the once-weekly schedule and 74.9% in the twice-weekly schedule(P=0.690).The median overall survival was not reached in either schedule.Also,the median progression-free survival and duration of response of the once-weekly schedule did not significantly differ from those of the twice-weekly schedule(8 months vs.10 months,P=0.545 and 6 months vs.7 months,P=0.467 respectively).Peripheral sensory neuropathy and grade 3/4 hematologic toxic effects were more frequently reported in the twice-weekly schedule than the once-weekly schedule,but there was no statistically significant difference.This preliminary experience in Chinese patients with newly diagnosed MM indicated that once-weekly infusion of Bortezomib plus dexamethasone may improve safety without affecting outcome.
文摘The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mostly of quartz, topaz and zinnwaldite (Li-rich mica) were exposed to further comminution by cone crusher and high voltage pulse power fragmentation. Product properties were analyzed by using a Mineral Liberation Analyser (MLA) and the obtained mineralogical and mineral processing relevant parameters were carefully evaluated with special focus on the characteristics of zinnwaldite. The results illustrate that both samples contain a significant quantity of very fine particles that are products of comminution. The modal mineralogy in the different sieve fractions is characterized by the accumulation of minerals of low hardness in the finest fraction and the enrichment of topaz, having a high hardness, in the somewhat larger fractions. Based on the results of mineral association data for zinnwaldite, a displacement of the muscovite-quartz ratio, in comparison to the results of modal mineralogy, was observed by indicating good quartz-zinnwaldite boundary breakage and weak muscovite-zinnwaldite breakage. Liberation as well as mineral grade recovery curves indicate that fraction 1000 to +500 μm is most suitable for beneficiation. The results of this study demonstrate that SEM-based image analysis, such as MLA, can effectively be used to investigate and evaluate phyllosilicate minerals in a fast and precise way. It is shown that the results of MLA investigations, such as modal mineralogy, are in good agreement with other analytical methods such as quantitative X-ray powder diffraction.
基金This work was financially supported by a grant from Nonferrous Corporation Africa Mining Public Limited Company and National Natural Science Foundation of China(No.51804020).
文摘As ore grades constantly decline,more copper tailings,which still contain a considerable amount of unrecovered copper,are expected to be produced as a byproduct of froth flotation.This research reveals the occurrence mechanism of copper minerals in typical copper sulfide tailings using quantitative mineral liberation analysis(MLA)integrated with scanning electron microscopy–energy dispersive spectroscopy(SEM–EDS).A comprehensive mineralogical characterization was carried out,and the results showed that almost all copper minerals were highly disseminated within coarse gangue particles,except for 9.2wt%chalcopyrite that occurred in the 160–180μm size fraction.The predominant copper-bearing mineral was chalcopyrite,which was closely intergrown with orthoclase and muscovite rather than quartz.The flotation tailings sample still contained 3.28wt%liberated chalcopyrite and 3.13wt%liberated bornite because of their extremely fine granularity.The SEM–EDS analysis further demonstrated that copper minerals mainly occurred as fine dispersed and fully enclosed structures in gangue minerals.The information obtained from this research could offer useful references for recovering residual copper from flotation tailings.
文摘The removal of iron from an Indian diaspore sample was studied using magnetic separation and leaching techniques aided by an in-depth mineralogical characterization study involving quantitative mineralogical evaluation by scanning electron microscope(QEMSCAN), electron probe micro-analyzer(EPMA) and X-ray diffraction(XRD). The characterization studies indicate that extremely fine-sized hematite grains are associated with several other mineral phases in a complex manner with around 60% of the hematite not liberated even below the size of 38 μm limiting the scope of physical separation processes to remove the iron. Wet high intensity magnetic separation(WHIMS) studies reveal that only 49% of iron can be removed. Further, leaching studies using oxalic acid suggest that around 76% of the iron can be removed under conditions such as a solid to liquid ratio of 0.05:1, a temperature of 90 ℃ a time period of 120 min and an acid concentration of 1 mol/L. The dissolution of iron in oxalic acid is found to be controlled by chemical reaction and the activation energy is calculated as 35.15 k J/mol.
文摘The influence of microwave treatment on the liberation of iron ore from the high phosphorus oolitic iron ore from Aswan region, Egypt was studied. The effect of microwave power, exposure time and grain size on the liberation of iron ore was investigated. The microfractures and cracks of the samples were characterized before and after microwave treatments. The heating rate of high phosphorus oolitic iron ore was studied. Crystallinity of hematite was characterized before and after microwave pretreatment. The results indicated that intergranular fractures formed between the gangues (fluorapatite and chamosite) and hematite after microwave treatment, leading to improved liberation of iron ore and a significant reduction in comminution energy. Percentages of fraction ≤ -0.125 mm increased from 46.6% to 59.76% with increased exposure time from 0 to 60 seconds. The heating rate of iron ore showed that microwave treatment was less efficient at smaller particle sizes for a fixed applied power density. Crystallinity of hematite increased with the microwave exposure time.
文摘AIM:To investigate variations in the incidence of peptic ulcers(PUs) in Taiwan by day of the week within age subgroups.METHODS:Ambulatory care data were retrieved from the Longitudinal Health Insurance Database 2000.There were 7204 subjects≥18 years-old with an emergency room admission claim for the treatment of PUs,resulting in a total of 9234 emergency room visits for PUs between 2009 and 2011.Data was divided into the seven days of the week and an additional variable for holidays.One-way analysis of variance was used to examine associations among the daily mean number of PU emergency room admissions and holidays/weekends/weekdays.RESULTS:One-way analysis of variance showed that there was a significant difference in emergency room admissions for PUs by the day of the week(P<0.001),with admission more likely to occur on Sundays or holidays than weekdays within the total and working populations.The weekday patterns of admission were similar for the patients aged 18-64 years and≥65years of age.Holidays,followed by Sundays,had higher PU admissions than the mean daily PU emergency room admissions.Furthermore,inclusion of only those treated for PUs with hemorrhage or perforation,Sundays and holidays had higher mean emergency room admissions than other days.Inclusion of patients who diagnosed with Helicobacter pylori infection,only holidays had higher mean emergency room admissions than other days.Inclusion of patients who had been prescribed non-steroidal anti-inflammatory drugs(NSAIDs)for over30 d,Sundays and holidays had higher mean PU ER admissions than other non-holiday weekdays.CONCLUSION:There is a higher incidence of emergency room admission for PUs on weekends than on weekdays for the total and working populations.